This invention relates to fluorescent lamp testing devices, and more particularly to a portable, self-contained testing device for testing a fluorescent lamp and lamp holder.
Fluorescent lamps typically include a glass envelope, such as a tube, containing an inert gas and mercury vapor, and having a coating of fluorescent material on the interior surface of its glass envelope. The tube contains thermionic cathodes at both ends which are connected to suitable terminal prongs, referred to as tube pins. The fluorescent lamp fits into an appropriate lamp holder having opposing pairs of sockets. Each socket receives a pair of tube pins, there being one pair of tube pins extending from each base end of the fluorescent lamp.
In various situations, a fluorescent lamp may fail to light. However, the problem may not be a deficiency in the lamp itself. For example, a short may exist in the lamp holder, or the starter or starter circuit may be deficient, or a problem may exist within the wiring. However, the first approach taken by the repairman is to replace the fluorescent lamp. Should the lamp still not be illuminated, they then proceed to search for other reasons for the inoperativeness. However, the original lamp which was removed may still be discarded since there is no easy way of testing whether the lamp is still adequate.
In some fluorescent fixtures, two or more fluorescent lamps are connected in series within the lamp holder and may be fed by a common ballast. When one of the lamps becomes inoperative, it will automatically cause all of the lamps connected in series therewith to stop illuminating. When the repairman comes to replace the fluorescent lamps, he does not know which lamp is the defective one and which one is still good. The normal procedure, however, is to replace all of the lamps and discard all of the removed lamps. In this manner, at least one good lamp is being automatically discarded for an inability to be able to test its operability.
In the prior art, there have been provided various testing units for fluorescent lamps. However, these were generally complex apparatus requiring removal of the lamp to a remote testing site, and inserting it into a fixed or stationary testing unit. In many situations, the particular testing device also tested for numerous efficiencies of the fluorescent lamp and accordingly was extremely difficult to use and costly. For example, the testing units would test for the gaseous discharge, the illumination capabilities of the fluorescent material on the surface, the thermionic contact circuit, and numerous other operative aspects of the fluorescent lamp in order to determine not only its operability, but its efficiency and adequacy.
Because most of these complex testing units were stationary, costly, and complex to utilize, in most situations they were never used by the average repairman during common repairs. As a result, numerous fluorescent lamps were automatically discarded because of the unavailability of a simple fluorescent lamp testing device.
Additionally, in many cases, a lamp may have been discarded only to discover that the problem existed within the lamp holder. However, again there was no immediate way of testing the lamp holder either, until after the new lamp was inserted. At that point, if the lamp still failed to illuminate, the repairman would proceed to determine which aspect of the lamp holder was deficient. However, initially the lamp would first be discarded and replaced before the repairman could determine that the problem originated in the lamp holder and not in the lamp.